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Oceanic Engineering, IEEE Journal of

Issue 3 • Date July 2010

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  • Table of contents

    Publication Year: 2010 , Page(s): C1 - C4
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  • IEEE Journal of Oceanic Engineering publication information

    Publication Year: 2010 , Page(s): C2
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  • Guest Editorial - Special Issue on Sediment Acoustic Processes: Part III

    Publication Year: 2010 , Page(s): 449 - 452
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  • Detailed Bathymetric Surveys Offshore Santa Rosa Island, FL: Before and After Hurricane Ivan (September 16, 2004)

    Publication Year: 2010 , Page(s): 453 - 470
    Cited by:  Papers (3)
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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3604 KB) |  | HTML iconHTML  

    Two weeks before Hurricane Ivan reworked the shores and nearshore seafloor of the northeastern Gulf of Mexico, swath bathymetry surveys were conducted with high-frequency (300 and 455 kHz) multibeam echosounders in three areas offshore Santa Rosa Island, FL, an 80-km barrier island extending west from Destin to Pensacola Bay, FL. These surveys were repeated in late October 2004, six weeks after the passage of the hurricane, allowing for quantitative pre- and posthurricane seabed comparisons. Bathymetric difference maps (0.2-0.3-m grid cells) show that sediment accretion exceeded 1 m in areas near the 6-7-m isobaths, where a submerged longshore bar was formed below the breaker zone of large storm waves. Accretion of sediment continued seaward tapering off near the 11-12-m isobaths, with evidence of slight seabed erosion (0.1-0.2 m) seaward of this boundary. Between the 6- and 12-m contour lines, the increase in sediment volume is about 279 000 m 3/km 2. Grab samples obtained in the area by Vaughan [IEEE J. Ocean. Eng., vol. 34, no. 4, pp. 495-515, 2009] support the hypothesis that the added material is fine sand eroded from the beach and dunes on Santa Rosa Island by the overwash and inundation associated with Ivan's storm surge and eventually deposited offshore by storm-surge ebb currents. Two-dimensional bottom roughness power density spectra computed from colocated east-west (EW) bathymetry swaths near the 12-m isobath show a post-Ivan threefold increase in root mean square (rms) roughness over the [0.104, 0.495] m-1 spatial wave number band. Bottom roughness spectrograms computed along individual north-south (NS) survey track lines perpendicular to the shoreline and extending 10 km offshore indicate that Ivan-induced waves and currents reworked the seabed to water depths of at least 22 m, with a twofold to fourfold increase in rms roughness over the [0.023, 0.156] m-1 spatial wave number band. View full abstract»

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  • Fine-Scale Volume Heterogeneity in a Mixed Sand/Mud Sediment off Fort Walton Beach, FL

    Publication Year: 2010 , Page(s): 471 - 487
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1652 KB) |  | HTML iconHTML  

    As part of the effort to characterize the acoustic and physical properties of the seafloor during the high-frequency 2004 Sediment Acoustics Experiment (SAX04), fine-scale variability of sediment sound speed and density was measured in a medium quartz sand using diver cores and an in situ conductivity probe. This study has a goal of providing environmental input to high-frequency backscatter modeling efforts. Because the experiment was conducted immediately following exposure of the site to Hurricane Ivan, measurements revealed storm-generated sedimentary structure that included mud deposits and trapped sand pockets suspended in the mud. Fluctuations of sediment sound speed and density were measured downcore at 1- and 2-cm increments, respectively, with standard laboratory techniques. Sediment density was also measured on a very fine scale with an in situ conductivity probe [in situ measurement of porosity (IMP2)] and by means of computed tomography (CT) imaging of a diver core. Overlap between the locations of the diver cores and the conductivity probe measurements allowed an examination of multiple scales of sediment heterogeneity and a comparison of techniques. Sediment heterogeneity was characterized using estimates of covariance corresponding to an algebraic form for the power spectrum of fluctuations obtained from core, conductivity, and CT measurements. Correcting for sampling brings the power spectra for density fluctuations determined from the various measurements into agreement, and supports description of heterogeneity at the site over a wide range of scales by a power spectrum having a simple algebraic form. View full abstract»

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  • Physical Pore Properties and Grain Interactions of SAX04 Sands

    Publication Year: 2010 , Page(s): 488 - 501
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1292 KB) |  | HTML iconHTML  

    During the 2004 Sediment Acoustic eXperiment (SAX04), values of sediment pore properties in a littoral sand deposit were determined from diver-collected cores using traditional methods and image analysis on X-ray microfocus computed tomography (XMCT) images. Geoacoustically relevant pore-space properties of sediment porosity, permeability, and tortuosity were evaluated at scales ranging from the pore scale to the core scale from “mud-free” sediments collected within the 0.07-km2 study area. Porosity was determined from water-weight-loss measurements to range from 0.367 to 0.369, from 2-D image analysis to range from 0.392 to 0.436 and from 3-D image analysis to range from 0.386 to 0.427. The range of permeability from all measurements was 2.8 × 10-11 m2 to 19.0 × 10-11 m2, however the range of permeability within each technique was much narrower. Permeability was determined using a constant head (CH) apparatus (krange = 2.88 to 3.74 × 10-11 m2), from a variant of the Kozeny-Carman (KC) equation (krange = 12.4 to 19.0 × 10-11 m2), from an effective medium theory technique (krange = 5.60 to 13.3 × 10-11 m2) and from a network model (krange = 8.49 to 19.0 × 10-11 m2 ). Permeability was determined to be slightly higher in the horizontal than in the vertical direction from the network model. Tortuosity ranged from 1.33 to 1.34. Based upon the small coefficients of variation for the conventionally determined pore-space properties, the sand sediment within these core samples was deemed homogeneous at all of the SAX04 sites. Additionally, grain interactions, specifically grain coordination number and grain contact areas, were determined from XMCT images. Grain contacts ranged in size from small point- - contacts of 136 μm2 to large-area contacts the size of grain faces ( >4500 × μm2). The mean coordination number was similar to that of a cubic packing (six), but sometimes exceeded 12, which is the coordination number for a hexagonal close packing of spheres. View full abstract»

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  • Time-of-Flight Measurements of Acoustic Wave Speed in a Sandy Sediment at 0.6–20 kHz

    Publication Year: 2010 , Page(s): 502 - 515
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1483 KB) |  | HTML iconHTML  

    There is considerable interest within the underwater acoustics community as to whether a fluid model or a poroelastic (Biot) model provides a more accurate representation of sandy sediments. One key metric used to determine this is the acoustic wave speed in the seabed, since the Biot model predicts a sound speed that is frequency dependent whereas the traditional fluid model assumes a sound speed that is constant with frequency. Results obtained during the 1999 Sediment Acoustics Experiment (SAX99) showed some evidence of sound-speed dispersion [IEEE J. Ocean. Eng., vol. 27, no. 3, pp. 413-428, 2002]. The results were consistent with Biot model predictions that employed inputs based on geophysical measurements made at the site. However, only a limited data set was obtained at frequencies from 1 to 10 kHz where the model exhibited its greatest sound-speed variation. Furthermore, these were relative-rather than absolute-measurements of sound-speed dispersion. During the SAX04 sea trial, conducted in autumn 2004 about a kilometer from the location of the SAX99 site, acoustic data were collected on receivers buried in the seabed using a pair of transmitters located within the seabed and a third located in the water column directly above the buried receivers. This source geometry enabled direct time-of-flight (TOF) measurements of acoustic wave speed along all three Cartesian axes. The results are normalized by the acoustic wave speed in the overlying water. Horizontal measurements yielded absolute dispersion estimates but the vertical data were limited to relative estimates due to uncertainty in the depths of the receivers. Results show dispersion within the error limits of the measurement with normalized sediment sound speed increasing from 1.05 at 600 Hz to 1.13 at 20 kHz. The frequency dependence of the measured sound-speed ratios reported on in this paper is in agreement with a simplified poroelastic model [J. Acoust. Soc. Amer., vol. 110, no. 5, pp. 2276-2281, 200- - 1] evaluated using physical parameters measured nearby during SAX99, but the measured sound-speed ratios are about 3% lower than the model predicts; however, some of the vibracores taken at the SAX04 site indicate the presence of small mud inclusions at about 1-m depth, and model results using the oases seismoacoustic model indicate that the lower sound speeds are consistent with the presence of a thin muddy layer. In addition, sound speed along the vertical axis showed substantially greater variability with frequency than did the measurements along the horizontal axes. Results obtained from a simple numerical model indicate that the greater variability in the vertical direction can be explained by interference from reflected arrivals from a low-speed reflector at approximately 1-m depth. Using the porosity β as a free parameter, a best fit of the poroelastic model to the data is obtained for β = 0.425 . Although this is higher than the value of β = 0.385 measured in the sandy sediment during SAX99, heuristic arguments based on the self-consistent model results and the vibracores are presented to support the hypothesis that localized muddy inclusions at the experimental site increased the average porosity over the horizontal propagation paths and resulted in the lower sound-speed ratios. View full abstract»

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  • Measurement and modeling of seabed particle motion using buried vector sensors

    Publication Year: 2010 , Page(s): 516 - 537
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1647 KB) |  | HTML iconHTML  

    A technique was developed to measure the speed of sound in marine sediments at discrete frequencies from 0.6 to 3 kHz by transmitting pulses from acoustic projectors within the water column and measuring the pressure and acceleration components of the acoustic field on vector sensors buried in the seabed. The burial depth and orientation of the vector sensors was determined by analyzing the amplitude and phase response of the acceleration signals to transmissions from three orthogonal directions, using two acoustic projectors also buried in the seabed and a third in the water column directly above the buried receivers. To determine the properties of the seabed, a sequence of transmitted pulses was repeated from ten different grazing angles, spanning from well above to near the nominal critical angle. Due to the interference of refracted and diffracted (mainly evanescent) components of the acoustic field that penetrate the seabed, the particle motion can be elliptical rather than rectilinear and is not necessarily aligned with the geometric ray path (i.e., according to Snell's law). A model was developed to quantify the effect of this interference. It revealed that the parameterization of the seabed as a sand half-space was incapable of explaining the frequency-dependent arrival angles measured by the vector sensors. Further modeling using a computer code for seismoacoustic propagation in horizontally stratified waveguides revealed that the measurement technique is very sensitive to the presence of thin layers with a high-impedance contrast. This modeling suggests that the presence of a thin muddy layer, 0.05-0.2 m thick within the top 1 m of the sediment, is dominating the complicated angular response of the vector sensors. View full abstract»

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  • Measurement of the frequency dependence of the sound speed and attenuation of seafloor sands from 1 to 400 kHz

    Publication Year: 2010 , Page(s): 538 - 557
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4079 KB) |  | HTML iconHTML  

    Measurements of sound speed and attenuation were performed over a frequency range from 1 to 400 kHz in the sandy seafloor near Ft. Walton Beach, FL, as part of the 2004 Sediment Acoustics Experiment (SAX04). The measurements at the lowest frequencies, from 1 to 20 kHz, were performed by transmitting tone burst signals from two acoustic sources positioned at depths up to 1 m below the seafloor which were recorded on a 4 m × 4 m array of 35 hydrophones emplaced to depths of between 0.1 and 1 m. Measurements were obtained at frequencies from 40 to 200 kHz with the In Situ Sediment Acoustic Measurement System (ISSAMS), a fixed linear array of four piezoelectric probes. The probes were inserted to a depth of 0.3 m, and the outer two probes were used as transmitters, with the inner probes acting as receivers. Sound-speed measurements were also made at 100, 200, and 400 kHz on diver-collected cores using four separate pairs of ultrasonic transducers. The sound-speed measurements above 40 kHz demonstrate an essentially constant sound-speed ratio with frequency of between 1.165 and 1.175, where the sound-speed ratio is the ratio of the speed through the sand to the speed through the overlying seawater. The sound-speed ratio determined from the low-frequency array data decreased from 1.135 to 1.115 with decreasing frequency below 20 kHz. Uncertainties in the sound-speed ratio values on the order of ±0.02 do not allow meaningful tests of the ability of Biot-Stoll or Buckingham propagation models to describe the observed dispersion. The measured attenuation values show a range from 1 to 120 dB/m with frequency from 1 to 400 kHz. At frequencies above 40 kHz, the attenuation follows a linear trend parallel to the estimates from the Buckingham model, as fit to the data with two free parameters, and at the highest frequencies significantly exceeding the Biot model prediction, as parameterized with values selected from the range of measurements of sediment and pore-w ater properties made from throughout the SAX04 site. At frequencies below 20 kHz, the data straddle the trends from the two models. View full abstract»

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  • Wave Power Absorption as a Function of Water Level and Wave Height: Theory and Experiment

    Publication Year: 2010 , Page(s): 558 - 564
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1531 KB) |  | HTML iconHTML  

    This paper investigates the sensitivity of a wave power system to variations in still water levels and significant wave heights. The system consists of a floating point absorber connected to a linear generator on the seabed. Changing still water levels are expected to affect the power absorption, since they will displace the equilibrium position for the generator translator. Similarly, changing significant wave heights will affect the rate at which the translator leaves the stator. Both these effects will in some cases result in a smaller active area of the stator. A theoretical expression to describe this effect is derived, and compared to measured experimental values for the wave energy converter L1 at the Lysekil research site. During the time of measurements, the still water levels at the site were in the range of [-0.70 m, +0.46 m ], and the significant wave heights in the range of [0 m, 2.7 m]. The experimental values exhibit characteristics similar to those of the theoretical expression, especially with changing significant wave heights. View full abstract»

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  • Numerical Modeling for an In Situ Single-Point-Mooring Cage System

    Publication Year: 2010 , Page(s): 565 - 573
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1209 KB) |  | HTML iconHTML  

    To mitigate marine pollution intensity at the sea bottom, an automatic rotating type of cage systems such as a single-point-mooring (SPM) cage system is often regarded as biofriendly equipment for fish farming in the open sea due to spreading uneaten waste feed and fish feces into a vast area. Though the SPM cage dynamic features under regular sea state have been investigated in previous researches, the in situ sea state is by no means a regular one, thus a further exploration of the dynamic response in the random sea is critical before deploying cages into the open sea. This work developed a numerical model for irregular sea states to simulate an SPM cage system in an unsheltered open sea, considering the environmental conditions as irregular waves combined with a steady uniform current. To validate the numerical model, a full-scale physical model was tested in the field, where both sea states and mooring line tension were recorded. Results indicate that the numerical model predictions have good agreement with field measurements in both time and frequency domains, while the net-volume deformation is presented numerically to show fish net space variation in a random sea. View full abstract»

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  • A Potential 4-D Fingertip Force Sensor for an Underwater Robot Manipulator

    Publication Year: 2010 , Page(s): 574 - 583
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1800 KB) |  | HTML iconHTML  

    The latest generation of underwater robots employ manipulators without force sensors. Accordingly, this paper presents a novel 4-D fingertip force sensor based on an E-type membrane for underwater robot manipulators. Specifically, this sensor is aimed at obtaining the accurate interaction force between underwater robot manipulators and other objects. Moreover, a seal technique and natural pressure compensation for the sensor are also described. The experimental results demonstrate strong linearity, high sensitivity, and weak couplings. View full abstract»

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  • An Efficient Digital CZT Beamforming Design for Near-Field 3-D Sonar Imaging

    Publication Year: 2010 , Page(s): 584 - 594
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (881 KB) |  | HTML iconHTML  

    A planar array of sensors is required to collect the signals coming from a 3-D scene to generate volumetric underwater acoustic images. The method most frequently used to process the acquired signals is a digital beamforming algorithm. In general, owing to the high number of sensors and beam signals, the computational load is prohibitive for real-time image generation. In the literature, a frequency-domain beamforming technique based on the chirp zeta transform (CZT), which is efficient and computationally advantageous, has been introduced for linear and planar arrays working in the far field. This paper proposes an extension of the CZT beamforming that has been specifically devised to cope with the requirements of volumetric sonar imaging. In particular, the processing of wideband signals collected by a planar array and generated by a scene placed in both near-field and far-field conditions is enabled with a computational load that is one or two orders of magnitude lower than that of the traditional frequency-domain and time-domain beamforming implementations. To attain this result, the Fresnel delay approximation, a useful definition of steering angles, and the setting up of multiple focal regions are adopted. In addition, a computationally convenient technique to generate cubic resolution cells is introduced. View full abstract»

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  • Improved torpedo range estimation using the fast orthogonal search

    Publication Year: 2010 , Page(s): 595 - 602
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (744 KB) |  | HTML iconHTML  

    A modified torpedo detection algorithm (MTDA) that improves upon the range estimates of an earlier torpedo detection algorithm (TDA) is presented in this work. The original TDA used the fast orthogonal search (FOS) algorithm to estimate the frequency of direct-path and a surface-reflected-path signal emitted by a torpedo. This technique assumed that the torpedo was traveling directly at the receiver and modeled the signals using sinusoidal functions. The range to the torpedo was estimated using the frequency estimates of the direct and reflected path and a trigonometric description of the approaching signals. The TDA was successful at detecting approaching torpedoes but had an average range error of 680 m. The modified torpedo detection addresses these deficiencies by: 1) estimating the angle between the approaching torpedo and the receiver and 2) using chirp signals as the candidates for FOS that model the theoretical direct- and reflected-path signals. In addition, the FOS algorithm is modified to fit the direct and reflected paths in pairs to eliminate the need to iterate the FOS algorithm. Signals of approaching torpedoes were simulated for several initial angles of approach using the generic sonar model (GSM) and waveform transmission through a channel (WATTCH) programs. The average error of the range estimates for sea state (SS0) 0 and 1 for the MTDA were 153 m as compared to 680 m for the TDA. In addition, the MTDA was shown to be resistant to false alarms. View full abstract»

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  • A geoacoustic bottom interaction model (GABIM)

    Publication Year: 2010 , Page(s): 603 - 617
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1041 KB) |  | HTML iconHTML  

    The geoacoustic bottom interaction model (GABIM) has been developed for application over the low-frequency and midfrequency range (100 Hz to 10 kHz). It yields values for bottom backscattering strength and bottom loss for stratified seafloors. The model input parameters are first defined, after which the zeroth-order, nonrandom problem is discussed. Standard codes are used to obtain bottom loss, uncorrected for scattering, and as the first step in computation of scattering. The kernel for interface scattering employs a combination of the Kirchhoff approximation, first-order perturbation theory, and an empirical expression for very rough seafloors. The kernel for sediment volume scattering can be chosen as empirical or physical, the latter based on first-order perturbation theory. Examples are provided to illustrate the various scattering kernels and to show the behavior predicted by the full model for layered seafloors. Suggestions are made for improvements and generalizations of the model. View full abstract»

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  • Detection of H -Phase Signals From Hydroacoustic Data Using Quadratic Classification

    Publication Year: 2010 , Page(s): 618 - 622
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (282 KB) |  | HTML iconHTML  

    The Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) operates a network of underwater hydrophones as part of the International Monitoring System (IMS). Data from this network are processed at the International Data Centre (IDC), Vienna, Austria. One of the objectives is to identify the signals that are due to an underwater explosion, the so-called H-phase signals. Data provided by IDC were examined to investigate new automated processing schemes that could significantly reduce the number of signals needed to be analyzed by human experts, while still detecting with high probability the rare H-phase signals. A variant of quadratic classification (QC) using four signal characteristics from the time, frequency, and cepstrum domains was applied to the problem. It was found that 97.5% of the received H-phase signals are detected by the automated QC process. These H-phase signals are among only about 1% of the signals which are allowed to form event solutions for further analysis by experienced experts. View full abstract»

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  • Adaptive Data Broadcasting in Underwater Wireless Networks

    Publication Year: 2010 , Page(s): 623 - 634
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (647 KB) |  | HTML iconHTML  

    Underwater acoustic networks have recently emerged as a new area of research in wireless networking. These networks can support a large number of applications such as environmental and underwater equipment monitoring. In recent years, there has been substantial work on protocol design for these networks with most efforts focusing on MAC and network layer protocols. Despite being a fundamental networking primitive, data broadcasting has so far received little attention in the context of underwater networks. This paper proposes an adaptive push system for dissemination of data in underwater acoustic wireless networks. Besides achieving adaptation of its broadcast schedule according to the a priori unknown needs of the clients, the proposed system also efficiently combats the problem of high latency of the underwater acoustic wireless environment. Simulation results show superior performance of the proposed system in the underwater environment compared to adaptations of existing terrestrial push systems. View full abstract»

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  • Adaptive Channel Estimation and Data Detection for Underwater Acoustic MIMO–OFDM Systems

    Publication Year: 2010 , Page(s): 635 - 646
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1699 KB) |  | HTML iconHTML  

    In this paper, frequency and time correlation of the underwater channel are exploited to obtain a low-complexity adaptive channel estimation algorithm for multiple-input-multiple-output (MIMO) spatial multiplexing of independent data streams. The algorithm is coupled with nonuniform Doppler prediction and tracking, which enable decision-directed operation and reduces the overhead. Performance is demonstrated on experimental data recorded in several shallow-water channels over distances on the order of 1 km. Nearly error-free performance is observed for two and four transmitters with BCH(64,10) encoded quadrature phase-shift keying (QPSK) signals. With a 24-kHz bandwidth, overall data rates of up to 23 kb/s after coding were achieved with 2048 carriers. Good results have also been observed in two other experiments with varying MIMO-OFDM (orthogonal frequency-division multiplexing) configurations. View full abstract»

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  • Configuration Optimization of Supercavitating Underwater Vehicles With Maneuvering Constraints

    Publication Year: 2010 , Page(s): 647 - 662
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1831 KB) |  | HTML iconHTML  

    This paper presents configuration optimization studies on supercavitating underwater vehicles. These innovative vehicles operate at extremely high speeds due to the drag reduction achieved through the supercavitating regime. Their dynamic behavior is complex and highly nonlinear which makes their guidance and control particularly challenging. The extreme performance of the vehicles and the complexity of their dynamic behavior drive the need for an integrated design tool that incorporates operational requirements as part of the design process. This study is a first attempt at optimizing the configuration of supercavitating vehicles, in terms of overall dimensions, mass distributions, and control surfaces size, while accounting for specific requirements related to operation at trim and during maneuvers. The optimization problem is formulated by considering range in straight level flight as the objective to be maximized, and by introducing conditions on trim operation and unsteady maneuvers as constraints. The maneuver requirements are defined by the solution of an optimal control problem, which, for a given vehicle configuration, yields optimal control inputs and corresponding vehicle state time histories. Results are presented to demonstrate the feasibility of the process and to investigate the effect of operational constraints on the final optimal vehicle configuration. The presented methodology considers a limited spectrum of operating conditions, but it is formulated in a way that allows its extension to include a number of such operational constraints, as required by specific mission requirements. View full abstract»

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  • Autonomous Underwater Vehicle Navigation

    Publication Year: 2010 , Page(s): 663 - 678
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (799 KB) |  | HTML iconHTML  

    This paper considers the vehicle navigation problem for an autonomous underwater vehicle (AUV) with six degrees of freedom. We approach this problem using an error state formulation of the Kalman filter. Integration of the vehicle's high-rate inertial measurement unit's (IMU's) accelerometers and gyros allow time propagation while other sensors provide measurement corrections. The low-rate aiding sensors include a Doppler velocity log (DVL), an acoustic long baseline (LBL) system that provides round-trip travel times from known locations, a pressure sensor for aiding depth, and an attitude sensor. Measurements correct the filter independently as they arrive, and as such, the filter is not dependent on the arrival of any particular measurement. We propose novel tightly coupled techniques for the incorporation of the LBL and DVL measurements. In particular, the LBL correction properly accounts for the error state throughout the measurement cycle via the state transition matrix. Alternate tightly coupled approaches ignore the error state, utilizing only the navigation state to account for the physical latencies in the measurement cycle. These approaches account for neither the uncertainty of vehicle trajectory between interrogation and reply, nor the error state at interrogation. The navigation system also estimates critical sensor calibration parameters to improve performance. The result is a robust navigation system. Simulation and experimental results are provided. View full abstract»

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  • 2011 IEEE membership form

    Publication Year: 2010 , Page(s): 679 - 680
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    Freely Available from IEEE
  • IEEE Oceanic Engineering Society Information

    Publication Year: 2010 , Page(s): C3
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    Freely Available from IEEE

Aims & Scope

The IEEE Journal of Oceanic Engineering (ISSN 0364-9059) is published quarterly by the IEEE Oceanic Engineering Society (IEEE OES). The scope of the Journal is the field of interest of the IEEE OES, which encompasses all aspects of science, engineering, and technology that address research, development, and operations pertaining to all bodies of water. This includes the creation of new capabilities and technologies from concept design through prototypes, testing, and operational systems to sense, explore, understand, develop, use, and responsibly manage natural resources.

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Meet Our Editors

Editor-in-Chief
N. Ross Chapman
School of Earth & Ocean Sciences
University of Victoria
3800 Finnerty Road
Victoria, BC V8P 5C2 Canada
chapman@uvic.ca